1. Technical Field
The present invention pertains to the field of wireless communication, especially via telecommunication networks according to 3GPP specifications. More particularly, the present invention pertains to uplinking or downlinking of packets in a UMTS radio access network, such as per HSUPA or HSDPA.
2. Discussion of Related Art
The present invention concerns the use of a data channel anticipated to be made available in WCDMA (Wideband Code Division Multiple Access) cellular networks—namely E-DCH (Enhanced-Dedicated Channel), an enhanced uplink channel. The WCDMA air interface is referred to as the UMTS (Universal Mobile Telecommunications System) terrestrial radio access network (UTRAN), specified by the third-generation partnership project (3GPP). E-DCH enhances the performance of the uplink compared to Release '99 of WCDMA (Rel99), reducing the delay and possibly increasing the capacity of the system. E-DCH is used by the so-called high speed uplink packet access (HSUPA) of UTRAN.
Per 3GPP, any UTRAN includes typically several radio network controllers (RNCs), each controlling several so-called Node Bs—also known as base stations. A UE (user equipment) device, such as a mobile phone, is allowed to uplink up to but not exceeding a maximum allowable rate or power that is communicated to the UE device by the Node B serving the UE device (a.k.a. the serving Node B). The serving Node B uses so-called scheduling information provided by the UE (and also the current availability of the network resources) to determine the maximum allowable rate or power the UE can use for uplink. The UE holds the data (packets) for uplink in a buffer until the packets are successfully communicated to the Node B. One example of scheduling information is how full the UE buffer is. Another is power status information.
Scheduling information is, per the prior art, communicated by the UE to the serving Node B either when event triggered (e.g., when the buffer content increases above some threshold), or periodically (e.g., every 50 ms), or when the UE is from time to time polled by the serving Node B. The scheduling information is sent in a so-called MAC-e PDU header (a header of a media access control layer-enhanced functionality protocol data unit) when there is also data to be sent (as opposed to the scheduling information), or as a separate MAC-e control PDU (which in practice may be a MAC-e PDU header without data).
Scheduling information requires some overhead (an overhead of 1-5 octets has been proposed) in the MAC-e PDU header, and therefore should not be sent too often (so as to avoid using up valuable UTRAN capacity). On the other hand it is advantageous, from the standpoint of optimizing use of a UTRAN, for a serving Node B of the UTRAN to get frequent reports of at least some scheduling information.
Thus, what is needed is a way for a UE device to frequently provide scheduling information to its serving Node B but to do so without using undue network capacity. Ideally, the way to do so could also be used to communicate not only scheduling information but also other kinds of information, and could be used not only in uplink (UE to Node B) but also in downlink.